The present invention relates generally to location and track or path-mapping systems, and more specifically to location and path-map-generation data acquisition and analysis systems that provide accurate, instantaneous position information and traversed-path data without relying on line-of-sight, extra-terrestrial satellites.
Traditional vehicular positional mapping and path-mapping systems include a first set of sensing devices (“sensors”) and a second set of inertial sensors or vehicle tracking sensors. The first set of sensors is adapted to record vehicle performance data while the second set of inertial sensors is adapted to determine the positional coordinates of the motor vehicle. Vehicle performance parameters can include, without limitation, lateral acceleration of the vehicle, longitudinal acceleration of the vehicle, wheel speed, engine revolutions per minute (“RPM”), throttle position, and steering angle. The second set of inertial sensors can include motion sensors and accelerometers, which, collectively, can be adapted to determine the heading direction (bearing) of the motor vehicle. Vehicle performance data, however, is of little use if it cannot be correlated to a precise location, which is to say, within approximately ±2-5 ft., of the motor vehicle.
Conventionally, data for determining the positional coordinates of a motor vehicle are provided by the Global Positioning System (“GPS”) or an equivalent system. However, to work properly, the GPS receiver must be able to lock-on to signals from at least three of the 24 satellites, to calculate a two-dimensional position, which is to say, longitude and latitude, and, further, to track movement. If three-dimensional positioning or attitude is required, which is to say, longitude, latitude, and altitude, signals from at least four satellites must be receivable.
An average positional accuracy for GPS receivers is only about 15 meters or about 50 ft. However, that accuracy can be affected by atmospheric conditions and other factors. For example, GPS signals can be denied or jammed in some urban settings due to the size or density of nearby structures and in some rural settings due to heavy canopies and mountainous terrain. GPS signals can also be denied or jammed when the receiver is located in a dwelling, a tunnel, a canyon, a cave, and so forth. As a result, GPS-based positioning and path-mapping systems are limited in their use and their accuracy.
The development of motion sensing devices, e.g., motion sensing accelerometers, gravitational accelerometers, gyroscopes, and the like, and their integration into small, portable devices have been suggested by others, to generate input signal data. For example, U.S. Pat. No. 7,138,979 to Robin, et al. discloses methods and systems for generating input signals based on the two-dimensional orientation of the portable device. Robin discloses using cameras, gyroscopes, and/or accelerometers, to detect changes in the spatial orientation of the device and, further, to generate positional signals that are indicative of that change.
Therefore, it would be desirable to provide a terrestrial location and path-map generation system that does not rely on the acquisition of signals from a plurality of satellites, to eliminate the aforementioned use restrictions. It would further be desirable to provide a location and path-map generation system that has a degree of accuracy of approximately ±2-5 ft.
Desirable applications of the location and path-map generation system include, without limitation, the ability to monitor the route of march of small mounted or dismounted units in all terrains and environments (day or night); to identify and designate objectives for small units in all terrains and environments; to transmit or re-transmit real-time location and imagery data to lowest echelon platform users during movement; and to generate precise path-map data of unmanned systems, such as drones, missiles, unmanned vehicles, robots, and so forth.
Accurate position and path-map information would be helpful to Armed Forces and Coast Guard personnel, fire fighters, police, search and rescue teams, and emergency medical response personnel. Recreational use, e.g., in hunting, hiking, boating, sailing, parasailing, parachuting, rappelling, mountain climbing, and the like, also would benefit from accurate positional information and traversed path data.